Speaking at the Royal Aeronautical Society last week, Walsh said "the A380 sales talk" indicated that the 550-seater "was the likeliest short-term relief in terms of runway pressure" for Heathrow, "providing effectively three slots for the price of two".

But he said that with Airbus conceding that initially "the aircraft's wake vortex problems are likely to lead to separations of an extra 2nm [3.7km]...for Heathrow, that means the A380's introduction is more likely to decrease capacity than increase it".

Walsh added: "Even if separation distances are eventually reduced, the likely slow growth of A380s in service will postpone any meaningful capacity advantage until well into the next decade."

Heathrow operator BAA says it does not believe the A380's arrival at Heathrow will cut capacity. It says Airbus is "still working on the vortex issue" and "it is too early to know what the outcome will be".

To counter the growing runway capacity issue at Heathrow, Walsh is calling for the UK government to quickly commit to a firm timetable to introduce mixed-mode operations (simultaneous take-offs and landings on both runways) and the construction of a third runway for operation from 2015. Heathrow currently handles 474,000 movements a year, and Walsh says the switch to mixed-mode operations could boost movements by 50,000-70,000, while adding a 2,000m (6,560ft)-long runway would enable movements to increase to 650,000-700,000 a year.

"With the A380 threatening to cut hourly capacity, it is essential we press ahead with mixed mode," says Walsh.

Now that Etihad Airways has elected to stop funding Air Berlin, forcing the German carrier to file for assembly, a central question is which parts of the business can continue to operate in the long term.